Our integrated team overcame a number of unique challenges to address discharge restrictions at Chestermere Lake caused by increased stormwater flows in east Calgary. The Shepard Stormwater Diversion Channel diverts stormwater from the Western Headworks Canal and conveys it to a new wetland treatment facility.
The project includes 3.1 kilometres of diversion channel; a 3 metre diameter tunnel under the Canadian Pacific Railway (CPR) mainline; 270 metres of deep buried, 3 metre diameter precast concrete pipe; a drop inlet structure for flow conveyance from the channel into the tunnel; and a large energy dissipation structure at the end of the closed conduit. The facilities were designed for a flow rate of 41 m3/s, with the closed conduit portion designed for a peak velocity of 7 m/s. A large underdrain conduit under the Western Headworks Canal is designed for 16 m3/s.
Building the tunneled crossing under five sets of CPR rail involved heavy dynamic loads and settlement restrictions. We solved this challenge by using a hand-dug tunnel, with a cast-in-place liner, built in the middle of winter.
Our structural, tunneling, and hydraulic experts, as well as experienced project managers and project engineers, made up the successful team. We met the client's expectations in a timely manner through our integrated services and availability of resources.